In recent years the public has become very much aware of the serious damage done to the aquatic ecology by the large oil spills that have resulted from accidents at offshore drilling cites, or that have befallen oil tankers at sea, near shore, or when actually in harbor.
At times, for reasons known only to the crew of a tanker, oil is pumped over-board.
Great sums of money and effort have been spent to clean up such spills. The prior art shows ships, barges, and floating tanks all provided with means for skimming oil and water off the sea surface, and transferring the mix to settling tanks and then recovering the oil from the tanks.
In some cases floating vessels use mops alleged to have a special affinity for oil. These mops are squeezed out on board the vessel and then reused to gather more oil.
All these devices above briefly mentioned are very expensive and deal with spectacular oil spills after they have happened, when the real problem is to provide means to prevent oil pollution of the marine environment.
The spectacular pollutors are not the only pollutors who are a menace to the marine environment.
There is a large group of vessels and boats, from fishing ships, to shrimp boats, crab-trap operators, pleasure crafts, and oyster gathering boats from which the bilge water, comprising a mixture of oil and water, is regularly pumped overboard.
All these operations take place off shore and in the many tidal streams, comprising small channels and big rivers, that separate literally hundreds of islands from the mainland. The greatest concentration of these waterways and islands in the United States is along the North Carolina, South Carolina, and Georgia coasts.
The islands are low and flat, regularly subject to tidal baths, and thus produce protein food in the marsh grass greater, the experts report, than in any comparable area of farm land.
All these vessels and boats are ideally suited for the installation on the craft of an oil and water separator to prevent pollution of the streams and marshland.
The prior art publications disclose not very many oil and water separators to used sued on the craft, and thus address the problem of preventing pollution.
Two examples of prior art, addressing the mentioned problem, are the U.S. Pat. to Niclausse U.S. Pat. No. 801,679 and the patent to Johnston U.S. Pat. No. 966,022.
From the literature of devices of this kind, such devices, possibly because of their high cost, or their mechanical complexity, or both, seem never to have been on the market, nor ever to have been in public use.
This invention provides for the separation of the oil from the bilge water in the hold of a ship by a device mounted on board that is, not affected by the ship's movements in roll or pitch, or both, and that is also "fail safe" by preventing unclean water from being pumped overboard.
A broad purpose of this invention is to prevent oil spills from a ship using the device embodying this invention so as not to damage the aquatic ecology.
As the description procedes reference will be made to a shrimp boat, but the use of this device on a shrimp boat is merely illustrative. The device may be used on any other type of boat as well, or may be designed as a large floating craft to gather oil and water off the surface of a body of water contaminated with an oil spill.
A shrimper has to carry a good bit of ice on-board his shrimp boat to keep his catch chilled, and, since the best shrimping takes place during the summer heat, there is considerable melting of ice. This ice water flows into the hold of the ship. The bilge water build-up is often augmented by annoying though not dangerous hull leaks. Frequent pumping of bilge water over-board is thus necessary.
However, this bilge water gets very contaminated and the major contaminant is oil. This oil usually is a mixture of oils such as crankcase oil from the engine, fuel oil, and other oils spread deliberately over the bilge water by the crew. The rationale of the deliberate spreading of oil on the bilge water by the crew is that the oil very effectively dampens the sloshing about of the bilge water and very effectively reduces stifling odors.
The great need therefore is to carry a bilge water cleaning device on-board, that is interposed between the bilge pump discharge opening and the final discharge opening, so that, by its use, only clean water goes over-board.
Other objects and merits of this invention will become apparent from the following detailed description when studied in the light of the accompanying drawings wherein like components, shown in the figures, are indicated by like numerals and wherein: